The popularity of vehicle sensing systems continues to increase. These systems serve to detect and track objects in relation to a moving vehicle. Examples of vehicle sensing systems include radars to support long range applications such as auto cruise control (ACC), and short-range radar (SRR) to support shorter range applications, such as parking aid, stop & go, and pre-crash detection. Of particular interest herein, is SRR.
In its current implementation, SRR is a 24-GHz coherent pulse radar which was designed for installation on automotive vehicles and is capable of detecting objects in range and bearing from 0 to 30 meters. To this end, the radar “dwells” at a particular discrete range to search for the presence of objects at that range before indexing to the next in a sequence of discrete ranges. Typical systems complete one 0-30 meter sweep during every 40-millisecond cycle. Object range of the object is determined from the particular range in which the object is observed. Estimation of the object's other target parameters (e.g., bearing), however, requires additional information that is made available through the radar's switched-beam monopulse design. In particular, the radar can switch between two overlapping antenna patterns, which will be referred to as the sum beam and the difference beam. Object bearing is calculated using signals from each antenna beam, as prescribed by monopulse theory.
Although gaining in popularity, SRR and other vehicle sensing systems continue to face significant problems. Among the more significant problems is the dwell time associated with determining target parameters. Specifically, sufficient dwelling to estimate target parameters is often implemented at each range, even if no object is present. This tends to slow the system's overall operation which can be particularly problematic in vehicle sensing systems since often the vehicle and the object are both moving rapidly, thereby necessitating essentially immediate detection of objects.
Therefore, there is a need for a vehicle sensing system which is more efficient in determining target parameters to increase operational speed, minimize computational overhead and reduce RF emissions. The present invention fulfills this need among others.